Apparatus for casting refractories



May 13, 1941. R. c. BENNE'R ETAL ,386

APPARATUS FOR CASTING REFRACTC'RIES Original Filed Nov. 9, 1937 2 Sheets-Sheet 1 INVENTORS, RAYMOND,C, BENNER y JOHN C. M MULLEN ATTORNEY.

May 13, 1941 c. BENNER ETAL 2,241,385

APPARATUS FOR CASTING REFRACTGRIES Original Fil ed Nov. '9, 1957 2.Sheets-S heet 2 ATTORNEY INVENTORS. v RAYMOND C. BENNER JOHN C. MCMULLEN Patented May '13, 1941 APPARATUS FOR CASTING REFRACTORIES Raymond C. Benner and John C. McMullen,

Niagara Falls, N. Y., assignors to The Carborundum Company, Niagara Falls, N. Y., a corporation of Delaware Original application November 9, 1937, SerialNo.

Divided and this application March 28, 1938, Serial No. 198,419

. 7 Claims.

This invention relates to an improvement in the method of manufacturing cast refractories. It relates particularly to a method of manufacturing cast refractory articles, such as bricks, in a manner that is quicker and more economical than the methods now used.

In the manufacture of glass tank blocks and other refractory shapes as hitherto practiced, the various component materials have been fused in an electric furnace of the arc type and thence tapped off into a cast iron or sand mold and the casting removed from the mold and covered with Udiatomaceous earth orthe like while cooling.

This method, although used extensively, has been found unsatisfactory from several standpoints. The cast iron molds generally used contain a large number of sections (from twelve to fourteen in most instances) and are dimcult to handle because of this and because of their relatively great weight. It is necessary for the operator to assemble and disassemble the mold each time a block is cast, and this requires considerable time. I

The sand molds used are fragile and hard to handle, and are good for only one cast.

Another disadvantage of the above-described method resides in the fact that it is necessary to fuse from 30%40% more material than is actually required for the block being cast, this additional material being used to fill the riser on the casting which is necessary to make a block having all faces smooth.

In the improved method described herein,- a

massive mold is used which has a relatively high heat capacity, has no riser and which requires no assembling or disassembling. Only enough material need be fused to fill the mold itself and the block may be removed from the mold almost immediately after pouring and placed in an an-' neallng kiln where it is annealed by its own heat. The refractory block made by our improved Fig. 3A is a side elevation of the mold shown in Fig. 3.

Fig.4 is a section along line IV-IV of Fig. 3.

Fig. 5 is a plan view of a modified form of mold.

Fi 6 is a side elevation of the mold shown in Fi 5.

Fig. 7 is a section along the line VII-VII of Fig. 5.

Fig. 8 is a sectional view of a further modification.

Fig. 9 shows a refractory brick made according to the improved process.

The apparatus comprises an arc ty'pe of furnace l 0 which differs from the conventional furnace in that it is constructed in such a manner that the electrodes ll remain in the bath at all times, even during the pouring operation. This is.accomplished by arranging the tips of the electrodes 1 I in the same horizontal plane as the axis of pour which is defined by the trunnion pins [2. It can be readily seen that when the pot i3 is tipped, by means of the cable ll, the electrodes need not be withdrawn while the molten material is being poured into the mold l5 through the pouring method has one rough face which is not objectionable inasmuch as all of the faces of the block are notin contact with the faces of adjacent blocks when the blocks'are assembled into a wall 'or the like. 3

For a better. understanding I of the invention a high heat capacity.

As shown in Figs. 1, 3 and 4, the mold consists of only five sections. The side sections are hinged to the rear section I8 by a pair of strap hinges I9. The bottom section 20 is rigidly attached to the back sectio l8 and is not as wide as the back section. Sid sections II have integral angular extensions 2| and 22 which form part {of the bottom of the mold. The purpose of splitting the bottom of the mold into three sec-' tions will appear as the description progresses.

The front of the mold 23 is attached to the bottom section 20 by a strap hinge 24 and is urged into vertical position by the compression spring reference is made to the accompanying drawings,

in which i Fig. 1 is a diagrammatic showing .of the furnace and mold used in the improved method.

.Fig. 2 is a sectional view of the furnace shown in Fig. 1.

Fig. 3 is a. plan view on a larger scale of the mold of Fig. 1.

25. Pins 26 mounted in front section 23 engage complementary depressions in side sections ll.

It can thus be seen that the mold is retained in its operating position by means of spring 25 and pin 26. Handles 21 are provided for opening the sides of themold, and a bail 28 is provided for holding open the front of the mold when desired. This ball 28 is adapted to be engaged with the hook-like projection 28 on the outer end of the lower spring support 30 (as shown in Fig. 3A) thereby holding the section 23 open against the pressure of the spring.

Figs. 1 and 3 show the positions of the various mold parts when the mold is ready for casting. After the material has been poured, it is allowed to set until a thin shell-has hardened around the sides and bottom of the block. This usually takes a minute, sometimes less, and during this interval the operator may smooth off the top of the block by raking.

After the thin shell has formed, the mold is opened. This is accomplished in the following manner:

The operator places the ball 28 under the hook 29 thus withdrawing pins 26 from their sockets in side sections 11. The handles 21 are then grasped by the operator and the sides II are opened outwardly. Because the angular projections 2i and 22 are integral with the side sections l1, they move outwardly therewith and a narrow edge is exposed on each side at the bot- .tom of the block. By placing a pair of lifting tongs under the exposed edges, the block may be lifted bodily from the mold and transferred to the annealing chamber.

The annealing chamber consists of a heat insulated chamber partly filled with diatomaceous earth. The partially solidified block is placed therein and completely covered with diatomaceous earth. The block is then left for several days or until it cools to approximately room temperature. By means of this method, expensive annealing ovens are rendered unnecessary and a considerable saving in fuel is effected because the heat of fusion of the material in the block is used to anneal it. The completed refractory block has a rough top surface, but this has been found to 'be of no disadvantage. It isan actual advantage in some installations; coke oven walls for instance, because it provides additional surface for contact with the hot gases.

the mold is automatically placed in readiness for another cast by the action of the springs 31.

Fig. 8 illustrates the arrangement used when casting very large blocks. Because these blocks are too large and heavy to handle with lifting tongs, they are cast in place in an annealing bin, the mold is removed from around the block after it has partially solidified and the block ls.covered with diatomaceous earth and left to anneal by its own heat.

In Fig. 8, 50 denotes the-annealing bin, and 5! a row of fire brick which are arranged on the floor of the bin and which support the mold. The mold is similar to that shown in Fig. 1 except that the bottom consists of three pieces instead of one. The center bottom section 52 is relatively thin, as compared to the other sections, and is supported on the fire brick by means of two wood strips 53. The other bottom pieces 54 are of the same height as the bottom proper and are unattached to the side sections or the center piece. v

After a cast has been made and the block has solidified around the bottom and sides, the side and back sections of the mold may be removed simply by opening the sides outwardly, and lifting the side and back sections (which are hinged together) bodily out of the bin. The

' front section (which in this case'is unattached Figs. 5, 6 and '1 show a modified form of mold.

This type of mold is easier and quicker to operate than the one just described and is used for casting brick of smaller size.

As can be seen from the drawings, the mold consists of a back section 30 rigidly attached to.

a bottom section 3| by means of bolts 32. Side sections 3334 and front section 35 are hinged to the bottomsection by means of strap hinges 38. A coiled compression spring 31 supported by projecting portions 43 extending from the bottom section or the lower portions of the side and front sections cooperates with each of the hinges to keep side and front sections of the mold in upright position. The side and'front sections are each provided with a rigid operating rod 38 which bears on the upper seat 39 of the respective coil spring. It

. will be obvious that the .springs 31 will tend to urge the front and side sections of the mold to v the closed position'at all times.

- The U-shaped operating lever 40 is pivotally mounted on the mold structure by means of bolts ll and sleeves l2, and rests on the rods 38. The weight of the lever 40 is not sufficient to compress the springs 31, but as is apparent from the drawingaafter the mold is filled with molten material, a slight pressure by the operator on the lever 40 will open slightly the side and front sections thereby allowing the partially solidified block to be removed from the mold. After the block is removed. the lever III is released and to the other sections) may then be removed. By this time, the heat of fusion of the molten material has penetrated through the relatively thin center piece 52 and has burned out the wood strips 53, allowing the center piece to drop heat in the block. It has been found that the tendency for the corners of the block to crack is greatly reduced if such a practice is followed.

were removed, leaving the bottom section to be I burned up by the heat given oil by the block in cooling. In the improved method just described, no top section at all is used, and all of the mold sections except -the narrow slabs 54 may be removed from around the block before the heat has damaged them.

Although graphite is preferred as a material for making any of the above described molds, cast iron or bonded silicon carbide may be used. In general, cast iron is the least desirable of the three materials because of its tendency to warp when subjected to high temperatures.

Bonded silicon carbide possesses several advantages over both graphite and cast iron and is preferred as a mold material in installations where expense is not a factor. y

In all cases, after the mold is removed from the block, the mold itselfis plunged into a cold water bath where it is rapidly cooled to room temperature. The mold is then ready for' another cast 'in a very short time.

Fig. 9 shoyvs a brick made by means of our improved process in the mold shown in Fig. 5.

This application is a division of our co-pending application, Serial No. 173,656, filed November 9, 1937.

We claim:

1. In a mold for casting very large refractory shapes, a mold bottom comprising a. plurality of unattached pieces, one of said pieces being relatively thinner than the others and being supported in place by a block of burnable material which ignites at a temperature substantially lower than that required to fuse the refractory material, whereby the thin bottom piece may be removed from the mold after the burnable material has burned.

2. An open top mold for casting refractory articles from molten refractory oxidic material comprising, a bottom section, a rear section rigidly attached to said bottom section, side and front sections hinged to said bottom section, projecting portions extending outwardly from the bottom of said side and front sections, said projecting portions supporting resilient means which normally engage second projecting portions extending outwardly from said side and front sections and thereby maintain said hinged side and front sections in closed position, and a single lever pivotally mounted at the rear section of said mold and engaging saidsecond projecting portions whereby external pressure exerted on said lever releases the force of said resilient .means against said hinged sections and opens said mold.

3. In an open top mold for casting refractory articles from molten refractory oxidic material, a body and hinged sections of a high heat ca- -pacity, said side sections hingedto the back' of said mold, said side sections having angular exhave a high heat capacity, projecting portions extending outwardly from the bottom of said side and front sections, said projecting portions supporting resilient means which normally engage second projecting portions extending outwardly from said side and front sections and thereby maintain said hinged side and front sections in closedposltion, and a single lever pivotally mounted on the rear section of said mold and resting on said second projecting portions whereby external pressure exerted on said lever releases the force of said resilient means against said hinged sections and opens said mold.

5. An open top mold for casting refractory articles from molten refractory oxidic material comprising side and front sections hinged to the body of said mold, said hinged sections and body having a high heat capacity, portions extending outwardly from said hinged sections to support and engage resilient means spaced from said mold walls, and resilient means supported by and engaging said projecting portions for normally retaining said hinged sections in closed positions, said resilient means being spaced from said wall sections of the mold.

6. An open top mold for casting articles from molten refractory oxidic material, said mold comprising side and front ections hinged to the body of said mold, said hinged sections and body having a high heat capacity, resilient means spaced from said mold walls but operably connected to said walls by intervening members for the purpose of normally retaining said mold walls in closed positions, whereby force exerted upon said resilient means will release the pressure retaining said mold walls in closed position and permit the mold to open, exposing the cast article.

7. An open top mold for casting articles from molten refractory oxidic material, said mold comprising a plurality of facing plates, each having a high heat capacity, resilient means normally holding said faces in proper position to de- A fine an article of the desired shape, intervening 4. An open top mold for casting refractory articles from molten refractory oxidic material comprising, a bottom section, a rear section rigid- 1y attached to said bottom section, side and front sections hinged to said rear and bottom sections respectively, saidhinged sections and body of the mold being of massive thickness whereby they members engaging said resilient means with said mold facing plates and a single control member operably connected to said intervening members and so arranged as to simultaneously retract each of said resilient means upon applying force to said single control member, whereby at least three molded faces of the cast article are exposed.

RAYMOND C. BENNER. JOHN C. McMULLEN. 

